The present invention relates to an absorption process using a desiccant brine as a working fluid to capture solar or waste heat using the combination of an air evaporator and vacuum boiler.
Kasley, U.S. patent Ser. No. 2,005,377, 1935, describes an absorption power plant using an inexpensive open-air evaporator and using tapwater as boiler feedwater. His plant uses the evaporative capacity of air to drive water from brine in an open cycle and thereby benefits from improved cycle efficiency and reduced costs. However, his plant also preheats water and brine streams to high temperatures and boils water directly to steam promoting undesirable corrosion and mineral deposits which may offset the great advantage of the open evaporator. Soddy, Great Britain, patent Ser. No. 716,665, 1954, and Isshiki, U.S. patent Ser. No. 4,122,688, 1978, describe low temperature (vacuum) processes and Natanson, U.S. patent Ser. No. 377,300, 1885, describes an indirect, flash-boiling process, but neither use the evaporative capacity of air to drive water from liquid desiccant brine in an open cycle. Features of the present invention described herein make the inexpensive, open evaporator practicable.